JP7482846B2 - Semiconductor photoresist composition and pattern formation method using the same - Google Patents

Description

The present invention relates to a semiconductor photoresist composition and a pattern formation method using the same.

EUV (extreme ultraviolet) lithography is attracting attention as one of the core technologies for manufacturing next-generation semiconductor devices. EUV lithography is a pattern formation technology that uses EUV light with a wavelength of 13.5 nm as the exposure light source. It has been demonstrated that EUV lithography can form extremely fine patterns (e.g., 20 nm or less) during the exposure step in the semiconductor device manufacturing process.

The realization of extreme ultraviolet (EUV) lithography requires the development of compatible photoresists capable of spatial resolutions of 16 nm or less. Currently, traditional chemically amplified (CA) photoresists are being researched and developed daily to meet the specifications for resolution, photospeed, feature roughness, and line edge roughness (LER) for next generation devices.

Intrinsic image blur due to acid catalyzed reactions in such polymeric photoresists limits resolution at small feature sizes, a fact that has long been known in e-beam lithography. Chemically amplified (CA) photoresists were designed for high sensitivity but can be more difficult under EUV exposure in part because their typical elemental makeup reduces the absorbance of the photoresist at 13.5 nm wavelengths, thereby reducing sensitivity.

CA photoresists also have difficulty with roughness issues at small feature sizes, and experiments have shown that line edge roughness (LER) increases as photospeed decreases, due in part to the nature of the acid catalyzed process. Due to the shortcomings and problems of CA photoresists, there is a demand in the semiconductor industry for a new class of high performance photoresists.

In order to overcome the drawbacks of the chemically amplified photoresist composition described above, inorganic photosensitive compositions have been researched. Inorganic photosensitive compositions are mainly used for negative tone patterning, which is resistant to removal by developer compositions due to chemical modification by a non-chemically amplified mechanism. Inorganic compositions contain inorganic elements with higher EUV absorption rates than hydrocarbons, and are known to ensure sensitivity even through a non-chemically amplified mechanism, have low sensitivity to stochastic effects, and have low line edge roughness and number of defects.

Inorganic photoresists based on peroxopolyacids of tungsten mixed with tungsten, niobium, titanium, and/or tantalum have been reported for patterning radiation sensitive materials (see US Pat. No. 5,399,313 and Non-Patent Document 1).

These materials have been effective in patterning large features in bilayer configurations with deep UV, x-ray, and e-beam sources. More recently, impressive performance has been shown when using cationic hafnium metal oxide sulfate (HfSOx) materials with peroxo complexing agents to develop 15 nm half pitch (HP) by projection EUV exposure (see U.S. Pat. No. 5,393,311 and U.S. Pat. No. 5,433,631). This system shows the best performance of non-CA photoresists and has a photospeed approaching the requirements for a viable EUV photoresist. However, hafnium metal oxide sulfate materials with peroxo complexing agents have several practical drawbacks. First, the material is coated with a highly corrosive sulfuric acid/hydrogen peroxide mixture and has poor storage stability. Second, as a complex mixture, it is not easy to modify the structure to improve performance. Third, it must be developed with a very high concentration of TMAH (tetramethylammonium hydroxide) solution, such as 25% by weight.

Recently, active research has been conducted on molecules containing tin since it was discovered that they have excellent extreme ultraviolet absorption. In the case of organotin polymers, one of these, alkyl ligands are dissociated by light absorption or the secondary electrons generated by it, and crosslinking with surrounding chains through oxo bonds enables negative tone patterning that is not removed by organic developers.

However, these organotin photoresists have the disadvantage of being sensitive to moisture.

U.S. Pat. No. 5,061,599 US Patent Application Publication No. 2011/0045406

H. Okamoto, T. Iwayanagi, K. Mochiji, H. Umezaki, T. Kudo, Applied Physics Letters, 49(5), 298-300, 1986 J. K. Stowers, A. Telecky, M. Kocsis, B. L. Clark, D. A. Keszler, A. Grenville, C. N. Anderson, P. P. Naulleau, Proc. SPIE, 7969, 796915, 2011

One embodiment of the present invention provides a composition for semiconductor photoresists that has excellent storage stability and sensitivity characteristics.

Another embodiment of the present invention provides a pattern formation method using the semiconductor photoresist composition.

A composition for semiconductor photoresist according to one embodiment of the present invention includes a condensate of an organotin compound represented by the following chemical formula 1 with at least one organic acid compound selected from the group consisting of substituted organic acids, organic acids containing at least two acid functional groups, and substituted or unsubstituted sulfonic acids; and a solvent.

In the above Chemical Formula 1,
R ¹ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or -L-O-R ^d ;
R ^a , R ^b and R ^c each independently represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof;
L is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms;
R ^d is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.

The condensate may contain constituent units derived from the organotin compound and constituent units derived from the organic acid compound in a mass ratio of 85:15 to 99:1.

The substituted organic acid is substituted with at least one selected from the group consisting of a heteroatom, an atomic group containing a heteroatom, and a combination thereof, the heteroatom being at least one selected from the group consisting of a sulfur atom (S), a nitrogen atom (N), an oxygen atom (O), a phosphorus atom (P), and a fluorine atom (F), and the atomic group containing a heteroatom can be at least one selected from the group consisting of -OH, -SH, -NH ₂ , -S-, and -S-S-.

The organic acid compound may be at least one selected from the group consisting of glycolic acid, malonic acid, succinic acid, 1,2,3,4-butanetetracarboxylic acid, citric acid, tartaric acid, tricarballylic acid, lactic acid, thioglycolic acid, dithiodiglycolic acid, thiodiglycolic acid, phthalic acid, maleic acid, L-aspartic acid, p-toluenesulfonic acid, methylsulfonic acid, and benzenesulfonic acid.

The pKa of the organic acid compound may be 5 or less.

The condensate may be at least one of an oligomer, a polymer, and a combination thereof.

The above condensation product may include a hydrolysis condensation product.

The semiconductor photoresist composition may further include additives such as a surfactant, a crosslinking agent, a leveling agent, or a combination thereof.

A method for forming a pattern according to another embodiment of the present invention includes the steps of forming a film to be etched on a substrate, applying the above-described semiconductor photoresist composition onto the film to be etched to form a photoresist film, patterning the photoresist film to form a photoresist pattern, and etching the film to be etched using the photoresist pattern as an etching mask.

The process for forming the photoresist pattern may use light in the wavelength range of 5 to 150 nm.

The pattern forming method may further include a step of forming a resist underlayer film between the substrate and the photoresist film.

The photoresist pattern may have a width of 5 nm to 100 nm.

The present invention provides a semiconductor photoresist composition that has excellent storage stability and sensitivity characteristics.

1 is a schematic cross-sectional view illustrating a method for forming a pattern using a semiconductor photoresist composition according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a method for forming a pattern using a semiconductor photoresist composition according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a method for forming a pattern using a semiconductor photoresist composition according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a method for forming a pattern using a semiconductor photoresist composition according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a method for forming a pattern using a semiconductor photoresist composition according to an embodiment of the present invention.

The following is a detailed description of an embodiment of the present invention with reference to the attached drawings. However, in describing the present invention, descriptions of already known functions or configurations will be omitted in order to clarify the gist of the present invention.

In order to clearly explain the present invention, parts that are not relevant to the explanation will be omitted, and the same or similar components will be given the same reference numerals throughout the specification. In addition, the size and thickness of each component shown in the drawings are shown arbitrarily for the convenience of explanation, and the present invention is not necessarily limited to what is shown.

In the drawings, the thickness of multiple layers and regions is exaggerated to clearly show them. Also, in the drawings, the thickness of some layers and regions is exaggerated for the convenience of explanation. When a layer, film, region, plate, etc. is said to be "on" or "above" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part between them.

In this specification, "substituted" means that a hydrogen atom is replaced with a deuterium atom, a halogen atom, a hydroxy group, an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a nitro group, a substituted or unsubstituted silyl group having 1 to 40 carbon atoms (e.g., an alkylsilyl group having 1 to 10 carbon atoms), an alkyl group having 1 to 30 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a cyano group. In this specification, "unsubstituted" means that a hydrogen atom remains as a hydrogen atom without being replaced with another substituent.

As used herein, unless otherwise defined, an "alkyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group. The alkyl group may be a "saturated alkyl group" that does not contain any double or triple bonds.

The alkyl group may be an alkyl group having 1 to 20 carbon atoms. More specifically, the alkyl group may be an alkyl group having 1 to 10 carbon atoms or an alkyl group having 1 to 6 carbon atoms. For example, an alkyl group having 1 to 4 carbon atoms means that the alkyl chain contains 1 to 4 carbon atoms, and indicates a group selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl.

Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

In this specification, unless otherwise defined, a "cycloalkyl group" refers to a monovalent cyclic aliphatic hydrocarbon group.

In this specification, unless otherwise defined, an "alkenyl group" refers to an aliphatic unsaturated alkenyl group that contains one or more double bonds as a linear or branched aliphatic hydrocarbon group.

In this specification, unless otherwise defined, an "alkynyl group" refers to an aliphatic unsaturated alkynyl group that contains one or more triple bonds as a linear or branched aliphatic hydrocarbon group.

As used herein, the term "aryl group" refers to a cyclic substituent in which all elements have p-orbitals and these p-orbitals form conjugation, including monocyclic or fused polycyclic (i.e., rings that share adjacent pairs of carbon atoms) functional groups.

The following describes a semiconductor photoresist composition according to one embodiment of the present invention.

A composition for semiconductor photoresist according to one embodiment of the present invention includes a condensate and a solvent, and the condensate is a condensate of an organotin compound represented by the following chemical formula 1 and at least one organic acid compound selected from the group consisting of substituted organic acids, organic acids containing at least two acid functional groups, and substituted or unsubstituted sulfonic acids.

In the above Chemical Formula 1,
R ¹ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or -L-O-R ^d ;
R ^a , R ^b , and R ^c each independently represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof;
L is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms;
R ^d is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.

In this specification, the term "condensate" is used to refer to a product produced by a condensation reaction, and the condensation reaction refers to a reaction in which at least two organic compound molecules are bonded to an active atom or atomic group at the center, thereby releasing a single molecule such as water, ammonia, or hydrogen chloride. Here, compounds produced by simply bonding two molecules are also included in the category of condensates.

The products may include monomers, oligomers, polymers, and combinations thereof.

As one embodiment of the present invention, R ¹ in the above Chemical Formula 1 may be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a combination thereof.

As a specific example, R ¹ in the above formula 1 may be a substituted or unsubstituted alkyl group having 3 to 20 carbon atoms.

For example, R ¹ in Formula 1 above can be an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, or a combination thereof.

For example, R ^a , R ^b , and R ^c in the above Chemical Formula 1 can each independently be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, or a combination thereof.

For example, R ^a , R ^b , and R ^c can each independently be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an ethenyl group, or a combination thereof.

The above R ^a , R ^b and R ^c may be the same or different.

By way of example, the substituted organic acid may be substituted with at least one of a heteroatom, a group of atoms that includes a heteroatom, and combinations thereof;
The heteroatom is at least one selected from the group consisting of a sulfur atom (S), a nitrogen atom (N), an oxygen atom (O), a phosphorus atom (P), and a fluorine atom (F);
The atomic group containing a heteroatom may be at least one selected from the group consisting of -OH, -SH, -NH ₂ , -S-, and -S-S-.

In this specification, a substituted organic acid means, for example, an organic acid that contains one acid functional group and in which at least one of the carbon atoms and hydrogen atoms contained in the hydrocarbon chain to which the acid functional group is linked is substituted with at least one of a heteroatom, an atomic group containing a heteroatom, or a combination thereof.

For example, in a substituted organic acid, at least one of the carbon and hydrogen atoms located at the end of the hydrocarbon chain to which the acid functional group is linked, at least one of the carbon and hydrogen atoms located in the middle of the hydrocarbon chain, and at least one combination thereof may be substituted with at least one heteroatom, an atomic group containing a heteroatom, and at least one combination thereof.

Examples of the substituted organic acids include glycolic acid, lactic acid, thioglycolic acid, and L-aspartic acid.

In this specification, the acid functional group may be, for example, a carboxyl group.

The organic acid containing at least two acid functional groups may be, for example, an organic acid containing 2 to 4 acid functional groups. Examples of such organic acids include malonic acid, succinic acid, 1,2,3,4-butanetetracarboxylic acid, citric acid, tartaric acid, tricarballylic acid, dithiodiglycolic acid, thiodiglycolic acid, phthalic acid, and maleic acid.

On the other hand, a substituted or unsubstituted sulfonic acid as used herein means an organic acid containing at least one -S(O) ₂ OH group.

Examples of substituted or unsubstituted sulfonic acids include p-toluenesulfonic acid, methylsulfonic acid, and benzenesulfonic acid.

On the other hand, the pKa of the organic acid compound may be 5 or less, for example 4 or less.

pKa is the negative logarithm (-log) of Ka, which is the acid dissociation constant when an acid (HA) dissociates into H ⁺ and ^A- in an aqueous solution, and the larger the pKa value, the weaker the acid is. When two or more acid dissociable functional groups exist in one organic acid molecule, the pKa value of the molecule is determined to be the value of the functional group with the lowest pKa.

When the pKa value of the organic acid compound is within the above range, it is easy to form a condensation product with the organotin compound, and the resulting condensation product is formed as an oligomer or higher polymer, which can reduce the penetration ability of external moisture.

Therefore, the storage stability of the semiconductor photoresist composition containing the organotin compound represented by the above chemical formula 1 and the condensate formed by the condensation reaction of the organic acid compound is excellent.

In the condensation product formed by the condensation reaction of the organotin compound represented by the above chemical formula 1 and the organic acid compound, the group derived from the organic acid compound acts as a ligand and links the organotin compound, so that the final condensation product can be at least one of an oligomer, a polymer, and a combination thereof.

For example, the condensation product may include a hydrolysis condensation product.

The condensate may contain the structural units derived from the organotin compound and the structural units derived from the organic acid compound in a mass ratio of 85:15 to 99:1. When the mass ratio is in this range, it is more advantageous in terms of film-forming properties, solubility, refractive index, and dissolution rate in a developer.

For example, the condensate may contain the organotin compound and the organic acid compound in a mass ratio of 90:10 to 99:1. Specifically, the mass ratio may be 90:10 to 97:3.

The condensate may have a weight average molecular weight (Mw) of 1,000 to 30,000 g/mol, for example 1,000 to 20,000 g/mol, and another example 1,000 to 10,000 g/mol. When the weight average molecular weight is in the above range, it is more advantageous in terms of film forming properties, solubility, refractive index, and dissolution rate in a developer. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

The conditions for obtaining the above condensation product are not particularly limited.

For example, the organotin compound represented by the above chemical formula 1 and the above organic acid compound can be diluted in a solvent such as PGMEA (propylene glycol monomethyl ether acetate), ethanol, 2-propanol, acetone, or butyl acetate, and water required for the reaction and an acid as a catalyst (hydrochloric acid, acetic acid, nitric acid, etc.) can be added as necessary, followed by stirring to complete the condensation polymerization reaction, thereby obtaining the desired condensation product.

The type and amount of the solvent, acid or base catalyst used here are not limited and may be selected as desired. The required reaction time varies depending on the type and concentration of the reactants, reaction temperature, etc., but is usually 15 minutes to 30 days. However, the reaction time is not limited to such ranges.

Commonly used photoresist compositions lack etching resistance, and there is a risk of pattern collapse due to high aspect ratios.

Meanwhile, a composition for semiconductor photoresist according to one embodiment of the present invention preferably contains the above-mentioned condensate and a solvent.

The solvent contained in the semiconductor photoresist composition according to one embodiment of the present invention may be an organic solvent, and examples thereof may include, but are not limited to, aromatic compounds (e.g., xylene, toluene), alcohols (e.g., 4-methyl-2-pentanol, 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol, propylene glycol monomethyl ether), ethers (e.g., anisole, tetrahydrofuran), esters (n-butyl acetate, propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), ketones (e.g., methyl ethyl ketone, 2-heptanone), mixtures thereof, and the like.

The semiconductor photoresist composition according to one embodiment of the present invention may further include additives, as needed. Examples of additives include surfactants, crosslinking agents, leveling agents, or combinations thereof.

Examples of surfactants that can be used include, but are not limited to, alkylbenzenesulfonates, alkylpyridinium salts, polyethylene glycols, quaternary ammonium salts, or combinations thereof.

Examples of crosslinking agents include, but are not limited to, melamine-based crosslinking agents, substituted urea-based crosslinking agents, acrylic-based crosslinking agents, epoxy-based crosslinking agents, and polymer-based crosslinking agents. Examples of crosslinking agents having at least two crosslink-forming substituents include compounds such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, 4-hydroxybutyl acrylate, acrylic acid, urethane acrylate, acrylic methacrylate, 1,4-butanediol diglycidyl ether, glycidol, diglycidyl 1,2-cyclohexanedicarboxylate, trimethylpropane triglycidyl ether, 1,3-bis(glycidoxypropyl)tetramethyldisiloxane, methoxymethylated urea, butoxymethylated urea, and methoxymethylated thiourea.

The leveling agent is used to improve the flatness of the coating film during printing, and any known leveling agent that is commercially available can be used.

The amount of these additives used can be easily adjusted depending on the desired physical properties, and they can also be omitted.

In addition, the semiconductor resist composition according to the present invention can use a silane coupling agent as an additive to improve adhesion to a substrate (for example, to improve the adhesive strength of the semiconductor resist composition to a substrate). Examples of the silane coupling agent include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane; or 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane; and silane compounds containing carbon-carbon unsaturated bonds such as trimethoxy[3-(phenylamino)propyl]silane.

According to the semiconductor photoresist composition of the present invention, even if a pattern having a high aspect ratio is formed, the pattern does not collapse. Therefore, in order to form a fine pattern having a width of, for example, 5 to 100 nm, for example, a fine pattern having a width of 5 to 80 nm, for example, a fine pattern having a width of 5 to 70 nm, for example, a fine pattern having a width of 5 to 50 nm, for example, a fine pattern having a width of 5 to 40 nm, for example, a fine pattern having a width of 5 to 30 nm, for example, a fine pattern having a width of 5 to 20 nm, the composition can be used in a photoresist process using light in a wavelength range of 5 to 150 nm, for example, a photoresist process using light in a wavelength range of 5 to 100 nm, for example, a photoresist process using light in a wavelength range of 5 to 80 nm, for example, a photoresist process using light in a wavelength range of 5 to 50 nm, for example, a photoresist process using light in a wavelength range of 5 to 30 nm, for example, a photoresist process using light in a wavelength range of 5 to 20 nm. Therefore, by using the semiconductor photoresist composition according to one embodiment of the present invention, extreme ultraviolet lithography using an EUV light source with a wavelength of 13.5 nm can be realized.

According to another embodiment of the present invention, a method for forming a pattern using the above-mentioned semiconductor photoresist composition can be provided. As an example, the pattern produced can be a photoresist pattern. More specifically, it can be a negative type photoresist pattern.

A method for forming a pattern according to one embodiment of the present invention includes the steps of forming a film to be etched on a substrate, applying the above-described semiconductor photoresist composition onto the film to be etched to form a photoresist film, patterning the photoresist film to form a photoresist pattern, and etching the film to be etched using the photoresist pattern as an etching mask.

The method for forming a pattern using the above-mentioned semiconductor photoresist composition will be described below with reference to Figures 1 to 5. Figures 1 to 5 are schematic cross-sectional views for explaining the pattern formation method using the semiconductor photoresist composition according to the present invention.

Referring to FIG. 1, first, an object to be etched is provided. An example of the object to be etched may be a thin film 102 formed on a semiconductor substrate 100. In the following, only the case where the object to be etched is the thin film 102 will be described. The surface of the thin film 102 is cleaned to remove contaminants remaining on the thin film 102. The thin film 102 may be, for example, a silicon nitride film, a polysilicon film, or a silicon oxide film.

Next, a resist underlayer film forming composition for forming a resist underlayer film 104 is applied to the surface of the cleaned thin film 102 by spin coating. However, the embodiment of the present invention is not necessarily limited to this, and various known coating methods such as spray coating, dip coating, knife edge coating, and printing methods such as inkjet printing and screen printing can also be used.

The process of coating the resist underlayer film can be omitted, and the following describes the case where the resist underlayer film is coated.

Then, a drying and baking process is performed to form a resist underlayer film 104 on the thin film 102. The baking process is performed at 100 to 500°C, for example, 100 to 300°C.

The resist underlayer film 104 is formed between the substrate 100 and the photoresist film 106, and can prevent the non-uniformity of the photoresist linewidth and the disruption of pattern formability when radiation reflected from the interface between the substrate 100 and the photoresist film 106 or from the interlayer hard mask is scattered into unintended photoresist regions.

Referring to FIG. 2, the above-mentioned semiconductor photoresist composition is coated on the resist underlayer film 104 to form a photoresist film 106. The photoresist film 106 may be in a form in which the above-mentioned semiconductor photoresist composition is coated on the thin film 102 formed on the substrate 100 and then hardened by a heat treatment process.

More specifically, the process of forming a pattern using the semiconductor photoresist composition may include a process of applying the above-mentioned semiconductor resist composition onto the substrate 100 on which the thin film 102 has been formed by spin coating, slit coating, inkjet printing, or the like, and a process of drying the applied semiconductor photoresist composition to form a photoresist film 106.

The composition for semiconductor photoresist has already been explained in detail, so we will not repeat the explanation here.

Next, a first baking process is performed to heat the substrate 100 on which the photoresist film 106 is formed. The first baking process can be performed at a temperature of 80 to 120°C.

Referring to FIG. 3, the photoresist film 106 is selectively exposed to light.

Examples of light that can be used in the exposure process include light with short wavelengths such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm), as well as light with high energy wavelengths such as EUV (Extreme UltraViolet; wavelength 13.5 nm) and E-Beam (electron beam).

More specifically, the light for exposure according to one embodiment of the present invention may be short-wavelength light having a wavelength range of 5 to 150 nm, or may be light having a high-energy wavelength such as EUV (Extreme UltraViolet; wavelength 13.5 nm) or E-Beam (electron beam).

In the process of forming the photoresist pattern, a negative type pattern can be formed.

The exposed regions 106a of the photoresist film 106 form a polymer through a crosslinking reaction such as condensation between organometallic compounds, and thus have a different solubility from the unexposed regions 106b of the photoresist film 106.

Next, the substrate 100 is subjected to a second baking process. The second baking process can be performed at a temperature of 90 to 200°C. By performing the second baking process, the exposed region 106a of the photoresist film 106 becomes less soluble in a developer.

FIG. 4 shows a photoresist pattern 108 formed by dissolving and removing the photoresist film 106b corresponding to the unexposed region using a developer. Specifically, the photoresist film 106b corresponding to the unexposed region is dissolved and then removed using an organic solvent such as propylene glycol monomethyl ether acetate (PGMEA), thereby completing the photoresist pattern 108 corresponding to a negative tone image.

As described above, the developer used in the pattern formation method according to one embodiment of the present invention may be an organic solvent. Examples of organic solvents used in the pattern formation method according to one embodiment include ketones such as methyl ethyl ketone, acetone, cyclohexanone, and 2-heptanone, alcohols such as 4-methyl-2-propanol, 1-butanol, isopropanol, 1-propanol, and methanol, esters such as propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate, n-butyl acetate, and butyrolactone, aromatic compounds such as benzene, xylene, and toluene, or combinations thereof.

As described above, the photoresist pattern 108 formed by exposure to light having wavelengths such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), as well as high-energy light such as EUV (Extreme UltraViolet; wavelength 13.5 nm) and E-Beam (electron beam) can have a thickness of 5 to 100 nm. The photoresist pattern 108 can be formed with a thickness of 5 to 90 nm, 5 to 80 nm, 5 to 70 nm, 5 to 60 nm, 5 to 50 nm, 5 to 40 nm, 5 to 30 nm, or 5 to 20 nm.

On the other hand, the photoresist pattern 108 may have a half-pitch of 50 nm or less, for example 40 nm or less, for example 30 nm or less, for example 20 nm or less, for example 15 nm or less, and a pitch with a line width roughness of 10 nm or less, 5 nm or less, 3 nm or less, 2 nm or less.

Next, the resist underlayer film 104 is etched using the photoresist pattern 108 as an etching mask. The organic film pattern 112 is formed by the above-described etching process. The formed organic film pattern 112 may also have a width corresponding to the photoresist pattern 108.

Referring to FIG. 5, the photoresist pattern 108 is applied as an etching mask to etch the exposed thin film 102. As a result, the thin film 102 is formed as a thin film pattern 114.

The thin film 102 can be etched by dry etching using, for example, an etching gas such as CHF ₃ , CF ₄ , Cl ₂ , BCl ₃ or a mixture thereof.

The thin film pattern 114 formed using the photoresist pattern 108 formed by the exposure process performed using an EUV light source may have a width corresponding to the photoresist pattern 108. For example, it may have a width of 5 to 100 nm, similar to the photoresist pattern 108. For example, the thin film pattern 114 formed by the exposure process performed using an EUV light source may have a width of 5 to 90 nm, 5 to 80 nm, 5 to 70 nm, 5 to 60 nm, 5 to 50 nm, 5 to 40 nm, 5 to 30 nm, 5 to 20 nm, similar to the photoresist pattern 108, and more specifically may be formed with a width of 20 nm or less.

The present invention will be described in more detail below with reference to examples relating to the production of the above-mentioned semiconductor photoresist composition. However, the technical features of the present invention are not limited to the following examples.

Synthesis Example 1: Synthesis of organotin compound 1 To a compound represented by the following chemical formula A-1 (10 g, 25.6 mmol), 25 ml of acetic acid was slowly added dropwise at room temperature, and the mixture was heated under reflux at 110° C. for 24 hours.

Then, the temperature was lowered to room temperature, and the acetic acid was vacuum distilled to obtain organotin compound 1 represented by the following chemical formula B-1 (yield: 90%).

Synthesis Example 2: Synthesis of organotin compound 2 To a compound (10 g, 25.4 mmol) represented by the following chemical formula A-2, 25 ml of acrylic acid was slowly added dropwise at room temperature, and the mixture was heated to reflux at 110°C for 24 hours.

Then, the temperature was lowered to room temperature, and the acrylic acid was vacuum distilled to obtain organotin compound 2 represented by the following chemical formula B-2 (yield: 50%).

Synthesis Example 3: Synthesis of organotin compound 3 To a compound (10 g, 23.7 mmol) represented by the following chemical formula A-3, 25 ml of propionic acid was slowly added dropwise at room temperature, and the mixture was heated to reflux at 110°C for 24 hours.

Then, the temperature was lowered to room temperature, and the propionic acid was vacuum distilled to obtain organotin compound 3 represented by the following chemical formula B-3 (yield: 95%).

Synthesis Example 4 Synthesis of Organotin Compound 4 To the compound represented by chemical formula A-2 in Synthesis Example 2 above (10 g, 25.4 mmol), 25 ml of isobutyric acid was slowly added dropwise at room temperature, and the mixture was heated to reflux at 110° C. for 24 hours.

Then, the temperature was lowered to room temperature, and the isobutyric acid was vacuum distilled to obtain organotin compound 4 represented by the following chemical formula B-4 (yield: 95%).

Synthesis Example 5: Synthesis of organotin compound 5 To a compound (10 g, 24.6 mmol) represented by the following chemical formula A-4, 25 ml of propionic acid was slowly added dropwise at room temperature, and the mixture was heated to reflux at 110°C for 24 hours.

Then, the temperature was lowered to room temperature, and the propionic acid was vacuum distilled to obtain organotin compound 5 represented by the following chemical formula B-5 (yield: 90%).

Examples 1 to 7
The organotin compounds obtained in each of Synthesis Examples 1 to 5 were mixed with the organic acid compounds shown in Table 1 below, and then PGMEA (propylene glycol methyl ether acetate containing 5% by mass of deionized water) was added to prepare solutions with a solid content of 20% by mass.

The above solution was stirred at 80°C for 24 hours, cooled to room temperature, and diluted with additional PGMEA to a solid content of 3% by mass to prepare a condensate-containing solution according to Examples 1 to 7 below. The solution was then filtered through a 0.1 μm PTFE (polytetrafluoroethylene) syringe filter to prepare a photoresist composition.

Comparative Examples 1 to 5
Each of the organotin compounds obtained in Synthesis Examples 1 to 5 was dissolved in PGMEA to a solid content concentration of 3 mass % and filtered through a 0.1 μm PTFE (polytetrafluoroethylene) syringe filter to prepare a photoresist composition.

Evaluation 1: Evaluation of Sensitivity and Line Edge Roughness (LER) The compositions according to Examples 1 to 7 and Comparative Examples 1 to 5 were spin-coated on a circular silicon wafer at 1500 rpm for 30 seconds to obtain a film, which was then exposed to extreme ultraviolet light (E-beam) at an accelerating voltage of 100 kV so that a 40 nm half-pitch nanoline pattern was formed. The exposed thin film was baked at 170° C. for 60 seconds, and then immersed in a Petri dish containing 2-heptanone for 30 seconds and removed. It was then washed with the same solvent for 10 seconds. Finally, the film was baked at 150° C. for 180 seconds, and a pattern image was obtained by FE-SEM (field emission scanning electron microscopy). The CD (Critical Dimension) size and line edge roughness (LER) of the formed lines confirmed from the FE-SEM images were measured, and the sensitivity and line edge roughness were evaluated according to the following criteria, and the results are shown in Table 2 below.

Evaluation criteria (1) Sensitivity The CD size measured at an energy of 1000 uC/ ^cm2 was evaluated according to the following criteria, and the results are shown in Table 2:
⊚: 40 nm or more; ◯: 35 nm or more and less than 40 nm; Δ: less than 35 nm; ×: no pattern is observed.

(2) Line Edge Roughness (LER)
◯: 4 nm or less △: more than 4 nm and less than 7 nm ×: more than 7 nm.

Evaluation 2: Evaluation of Storage Stability Meanwhile, the storage stability of the photoresist compositions according to Examples 1 to 7 and Comparative Examples 1 to 5 was evaluated according to the following criteria, and the results are shown in Table 2 below:
[Storage stability]
The photoresist compositions according to Examples 1 to 7 and Comparative Examples 1 to 5 were left at room temperature (20±5° C.) for a certain period of time, and the degree of precipitation was observed with the naked eye and evaluated on a two-level scale according to the following storage criteria:
*Evaluation criteria: ◯: Can be stored for 6 months or more; △: Can be stored for 3 months or more but less than 6 months; ×: Can be stored for less than 6 months.

Referring to Table 2, it can be seen that the semiconductor photoresist compositions of Examples 1 to 7 have better storage stability than Comparative Examples 1 to 5, and it can also be seen that the patterns formed using the semiconductor photoresist compositions of Examples 1 to 7 show better sensitivity and line edge roughness (LER) than Comparative Examples 1 to 5.

Although specific embodiments of the present invention have been described and illustrated above, the present invention is not limited to the described embodiments, and it will be obvious to those of ordinary skill in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations should not be understood individually from the technical spirit and perspective of the present invention, and the modified embodiments can be said to fall within the scope of the claims of the present invention.

100 substrate,
102 thin film,
104 resist underlayer film,
106 Photoresist film,
106a exposure area,
106b unexposed area;
108 Photoresist pattern,
112 organic film pattern,
114 Thin film pattern.

Claims (6)

A composition obtained by mixing and heating an organotin compound represented by the following chemical formula 1 and at least one organic acid compound selected from the group consisting of glycolic acid, malonic acid, succinic acid, and 1,2,3,4-butanetetracarboxylic acid ; and a composition for semiconductor photoresist, comprising :

In the above Chemical Formula 1,
R ¹ is an unsubstituted alkyl group having 1 to 20 carbon atoms;
R ^a , R ^b , and R ^c are each independently an unsubstituted alkyl group having 1 to 20 carbon atoms , or an unsubstituted alkenyl group having 2 to 20 carbon atoms. 2. The semiconductor photoresist composition of claim 1 , further comprising an additive selected from the group consisting of a surfactant, a crosslinking agent, a leveling agent, and combinations thereof. forming a film to be etched on a substrate;
A step of forming a photoresist film by applying the semiconductor photoresist composition according to claim 1 or 2 onto the film to be etched;
patterning the photoresist film to form a photoresist pattern; and etching the film to be etched using the photoresist pattern as an etching mask.
A pattern forming method comprising: 4. The pattern forming method according to claim 3 , wherein the step of forming the photoresist pattern uses light having a wavelength in the range of 5 to 150 nm. The pattern forming method according to claim 3 , further comprising the step of forming a resist underlayer film between the substrate and the photoresist film. 6. The pattern forming method according to claim 3 , wherein the photoresist pattern has a width of 5 to 100 nm.